A cashier and a security guard of a toll plaza were on Sunday shot dead by two assailants in a suspected robbery bid in southeast Delhi's Badarpur area, police said.

The bike-borne assailants opened fire at cashier Manmohan Singh Sharma, 60, and guard Mahipal, 50, in the wee hours at staff quarter near the toll collection centre in Badarpur.

The location of the Badarpur toll plaza.

Both were rushed to a hospital where they succumbed to injuries, police said.

Preliminary investigation indicates that it was a case of robbery gone wrong, police said. The two employees were custodians of around Rs 2.50 crore cash collected at the toll plaza over a period, police added. However, police are also probing the angle of personal rivalry.

It also appears that the assailant duo took with them a laptop bag. A team has been constituted to track them down, police said.

During the firing, the locals raised an alarm and the police were informed. Senior officials of the district also visited the spot, they said. A case of murder has been registered and investigation is underway, police added.